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Allow enabling sand duping (#10191)

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Because this exploit has been widely known for years and has not been fixed by Mojang, we decided that it was worth allowing people to toggle it on/off due to how easy it is to make it configurable.

It should be noted that this decision does not promise all future exploits will be configurable.
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Owen 2024-03-03 17:05:34 -05:00 • committed by GitHub
parent b21eb4d9a4
commit 89d51d5f29
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673 changed files with 157 additions and 189 deletions
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patches/server/0954-Optimize-VarInts.patch Normal file
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@ -0,0 +1,52 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: astei <andrew@steinborn.me>
Date: Sat, 28 Oct 2023 19:46:21 -0400
Subject: [PATCH] Optimize VarInts
https://github.com/PaperMC/Paper/pull/6957#issuecomment-985250854
diff --git a/src/main/java/net/minecraft/network/VarInt.java b/src/main/java/net/minecraft/network/VarInt.java
index 18d5a22ad3ef4cb279475531dbc2c65e07c69929..3f362eb42587b333e27b9cf25588a9cfcb8a56e7 100644
--- a/src/main/java/net/minecraft/network/VarInt.java
+++ b/src/main/java/net/minecraft/network/VarInt.java
@@ -9,6 +9,18 @@ public class VarInt {
private static final int DATA_BITS_PER_BYTE = 7;
public static int getByteSize(int i) {
+ // Paper start - Optimize VarInts
+ return VARINT_EXACT_BYTE_LENGTHS[Integer.numberOfLeadingZeros(i)];
+ }
+ private static final int[] VARINT_EXACT_BYTE_LENGTHS = new int[33];
+ static {
+ for (int i = 0; i <= 32; ++i) {
+ VARINT_EXACT_BYTE_LENGTHS[i] = (int) Math.ceil((31d - (i - 1)) / 7d);
+ }
+ VARINT_EXACT_BYTE_LENGTHS[32] = 1; // Special case for the number 0.
+ }
+ public static int getByteSizeOld(int i) {
+ //Paper end - Optimize VarInts
for(int j = 1; j < 5; ++j) {
if ((i & -1 << j * 7) == 0) {
return j;
@@ -39,6 +51,21 @@ public class VarInt {
}
public static ByteBuf write(ByteBuf buf, int i) {
+ // Paper start - Optimize VarInts
+ // Peel the one and two byte count cases explicitly as they are the most common VarInt sizes
+ // that the proxy will write, to improve inlining.
+ if ((i & (0xFFFFFFFF << 7)) == 0) {
+ buf.writeByte(i);
+ } else if ((i & (0xFFFFFFFF << 14)) == 0) {
+ int w = (i & 0x7F | 0x80) << 8 | (i >>> 7);
+ buf.writeShort(w);
+ } else {
+ writeOld(buf, i);
+ }
+ return buf;
+ }
+ public static ByteBuf writeOld(ByteBuf buf, int i) {
+ // Paper end - Optimize VarInts
while((i & -128) != 0) {
buf.writeByte(i & 127 | 128);
i >>>= 7;